toc1955's video: Pockels Effect Experiments

Pockels Effect Experiments (Adolf Cortel, August 2020) Some experiments on the Pockels effect in a crystal of lithium niobate can be watched in the video. The crystal has been cut so that the light propagates in the direction of the optic axis and an electric field E can be applied in a direction perpendicular. (In the commercial equipment to demonstrate this effect as Leybold, 3B.. E is applied in the direction of the optic axis). The video displays how: 1. The electric field changes the plane of polarization of the light (from a laser diode or a He-Ne laser). This can be observed using a regulated HV power supply or with a simple piezoelectric piezo sparker, or even with a plexiglas charged rod. 2. Under conoscopic ligthing (by using a lens in front of the crystal) a beautiful uniaxic interference figure can be cast in a screen. This figure turns to biaxial when the electric field changes the refractive index in one of the directions perpendicular to the optic axis (in the plane xy). This is observed with a laser as well as in the stage of a polarizing microscope. If interested in seing the Pockels effect in a polarizing microscope you can watch my video: https://youtu.be/rRrHIV7dRIA 3. By polishing two extra faces of the crystal, and with the laser and the electric field both perpendicular to the optic axis, it appears the interference figure that the crystallographers call uniaxic flash figure. The index of refraction of the crystal in the direction of E changes, and so does the interference figure. The music is a fragment of the “Butterfly lovers concerto” performed by Ji-Won Song (violin) and Beilin Han (piano). I Have no rights on this music and I'm using it only for the education purposes to which the video is aimed.